A discrete Particle Swarm Optimization(PSO) algorithm was presented for Job Shop scheduling problem.In the algorithm,a sequence-based code and update strategy for new positions were applied so as to make PSO more suitable for scheduling problems.Aiming at the shortcoming of premature and poor resulted from pure PSO,based on the complementary strengths of PSO and Variable Neighborhood Search(VNS) algorithm,four hybrid procedures were put forward.They were first PSO then VNS(PV) algorithm,Enhanced PSO(EPSO) a...